This application is based on and incorporates herein by reference Japanese Patent Application Nos. Hei. 11-290457 filed on Oct. 13, 1999, and 2000-303938 filed on Oct. 3, 2000.
1. Field of the Invention
The present invention relates to an intake air controller suitable for use in an internal combustion engine, to which a throttle assembly including a throttle valve is attached
2. Description of Related Art
U.S. Pat. No. 5,341,773 discloses an intake air controller for an internal combustion engine, to which a throttle assembly including a throttle valve is attached. The throttle assembly made of resin is attached to intake air passages of the intake air controller. A sealing mechanism between the throttle assembly and the intake air passages includes O-rings axially sealing therebetween and a U-shaped pin preventing the throttle assembly from separating from the intake air passage.
However, according to U.S. Pat. No. 5,341,773, since the throttle assembly is disposed between the intake air passages, both ends of the throttle assembly have to be sealed. Thus, the throttle assembly is not easily attached to the intake passages, and the sealing mechanism is complicated to prevent a stress strain.
An object of the present invention is to provide an intake air controller in which a throttle body is easily attached to an intake air passage body, a sealing mechanism therebetween is simplified, and stress strain due to fixing force is prevented.
According to a first aspect of the present invention, a throttle assembly to which a seal member is previously attached is inserted into a slot, and first and second flanges are fixed to each other. That is, the throttle assembly including the seal member is inserted into the slot, so that the throttle assembly is easily attached to the intake air passage body, and a sealing mechanism therebetween is simplified.
According to a second aspect of the present invention, a first flange formed in the throttle body is fixed to a second flange formed in the intake air passage body by a screw, a snap fit, or a spring cramp. Thus, a sealing performance is improved and a bore wall is not distorted due to the fixing force, so that a throttle valve smoothly operates to attain an appropriate clearance between the throttle valve and the bore wall, thereby improving the control of the intake air flow amount.
According to a third aspect of the present invention, since an additional insertion portion is installed into and held by a holder portion while no seal member is provided therebetween, the axis of the insertion portion is made to correspond to the axis of the holder portion. Thus, a clearance between the outer wall of the insertion portion and the inner wall of the slot is constantly maintained, so that the sealing performance of the seal member is highly improved.
Further, the insertion portion is firmly supported by the holder portion, thereby preventing the insertion portion from vibrating due to an engine vibration.